1. Field of the Invention
The present invention relates to a head-protecting airbag apparatus provided with a head-protecting airbag body which is accommodated from a pillar portion along a roof side rail portion and is inflated in a curtain shape by gas injected from an inflator when at least predetermined high load acts on a vehicle side body.
2. Description of the Related Art
For the purpose of improvement in performance for protecting the head of a vehicle occupant sitting on a front seat when at least predetermined load acts on a vehicle side body, there has been proposed a head-protecting airbag apparatus where an airbag body accommodated in a folded state from a front pillar portion along a roof side rail portion is inflated in a curtain shape along a side window glass. A configuration of a head-protecting airbag apparatus disclosed in WO 96/26087 will be explained below.
As shown in FIG. 21, a head-protecting airbag apparatus 400 is configured as main elements with an elongated duct 406 disposed from a front pillar portion 402 along a roof side rail portion 404, an airbag body 412 accommodated in its folded state within the duct 406 and fixed at a front end fixing point and a rear end fixing point on a vehicle body side, an inflator connected to a rear end of the duct 406 through a hose 414, for injecting gas when a predetermined or higher high load acts on a vehicle side portion, and a strip-like strap whose one end portion is fixed at a vehicle body side and the other end thereof is fixed to a rear end portion of the airbag body 412. Further, the airbag body 412 is configured by connecting a plurality of cells 420 in parallel, each cell being formed in an almost cylindrical shape and disposed such that its longitudinal direction is directed to an almost vertical direction.
According to the above configuration, when a predetermined or higher load acts on the vehicle body side portion, gas is injected from the inflator 416. For this reason, the gas injected flows into the respective cells 420 of the folded airbag body 412 through the hose 414 and the duct 406. As a result, the respective cells 420 are inflated in an almost cylindrical shape whose longitudinal direction corresponds to an almost vertical direction of a vehicle, so that the airbag body 412 is inflated in a curtain configuration. Furthermore, since the rear end portion of the airbag body 412 is connected to the vehicle body side through the strap 418, the rear side of the airbag body 412 is securely positioned inside an upper portion of a center pillar portion 424 of the vehicle.
However, in such a head-protecting airbag apparatus, when a folded airbag body is inflated, a lower portion of the airbag body is moved downwardly along a pillar garnish disposed at an inside portion of a center pillar portion in an occupant compartment. At this time, in a vehicle where an occupant compartment projection such as a slip joint is disposed, it is considered that a lower portion of the airbag body during its expansion may be caught up by the vehicle occupant compartment projection so that an appropriate expansion of the airbag body may be prevented.
In view of the above fact, an object of the present invention is to provide a head-protecting airbag apparatus which is difficult to be caught up by an occupant compartment projection and is capable of improving an expansion performance.
A first aspect of the present invention is a head-protecting airbag apparatus where an airbag body inflated in a curtain shape is mounted in a folded state along a roof side rail across at least a center pillar, wherein an upper portion of the airbag body projects in an occupant compartment before expansion of a lower portion of the airbag body.
Accordingly, when the airbag is inflated, gas introduced into the airbag body from the upper portion inflates the upper portion and inflates the lower portion of the airbag body downwardly in the occupant compartment. At this time, since the airbag body is folded such that the upper portion is inflated earlier than the lower portion at the expansion time, the lower portion of the airbag body is pushed out by the upper portion which has projected in the occupant compartment. As a result, the lower portion of the airbag body with a pushed-out state is inflated and expanded towards a lower portion of the vehicle body. Therefore, the lower portion of the airbag body is moved downwardly at a position where it is spaced from such an occupant compartment projection as a slip joint. Accordingly, in a vehicle where there is the occupant compartment projection at an area where the airbag body is inflated, it becomes hard that the lower portion of the airbag body may be caught up by the occupant compartment projection during the expansion, thereby improving a expansion performance of the airbag body.
A second aspect of the invention is a head-protecting airbag apparatus where an airbag body inflated in a curtain shape is mounted in a folded state along a roof side rail across at least a center pillar, wherein the airbag body comprises:
an upper portion folded in a bellows shape; and
a lower portion subjected to one of turning-back performed toward an occupant compartment inner side and rolling-up performed towards the occupant compartment inner side.
According to this aspect, when the airbag body is inflated, the lower portion which has been subjected to the turning-back/rolling-up is pushed out inward the occupant compartment by the upper portion which has projected in the occupant compartment. Next, when the lower portion of the airbag body is turned back, the lower portion with a pushed-out state towards the occupant compartment inner side is inflated and expanded so as to pivot downwardly about the turned-back portion from the occupant compartment inner side towards an occupant compartment outer side. Therefore, the lower portion of the airbag body is moved downwardly at a position where it is spaced from such an occupant compartment projection as a slip joint inward the occupant compartment. That is, the lower portion is moved so as to cover the occupant compartment projection from an occupant compartment inner side. Alternatively, when the lower portion is rolled or folded in a rolling-up manner, the lower portion is unrolled downwardly from the occupant compartment inner side. As a result, the lower portion of the airbag body can easily ride over a occupant compartment projection such as a slip joint. Accordingly, in a vehicle where there is an occupant compartment projection at an area where the airbag body is inflated, it is hard that the lower portion of the airbag body is caught up by the occupant compartment projection during expansion, thereby improving expansion performance of the airbag body.
A third aspect of the invention can be configured in the second aspect such that the turning-back is performed so as to position a distal end portion of the airbag body on an upper face of the upper portion, it is performed so as to position the distal end portion on a occupant compartment inner side of the upper portion, or it is performed so as cover the upper portion from the occupant compartment inner side. The airbag body is thus turned back so that the upper portion folded in the bellows is substantially covered with the lower portion. As a result, in a stage where the airbag body is delivered prior to assembling the airbag body, a drawback is reduced that foreign matters are caught up into the bellows portion.
A fourth aspect of the invention can be structured in the second aspect such that the turning-back is performed so as to position a portion of the airbag body positioned below a turning-back line set at an intermediate portion, in a vertical direction, of the lower portion at the occupant compartment inner side and the rolling-up is performed upwardly from the turning-back line towards the occupant compartment inner side.
According to this aspect, when the airbag body is inflated, gas introduced into the airbag body from the upper portion inflates and expands the bellows portion of the upper portion of the airbag body approximately downwardly along a center pillar, and it inflates and expands the rolled portion of the airbag body downwardly in the occupant compartment. At this time, in the rolled-up portion, the roll is unrolled at first and then the turned-back portion which has been turned back upwardly is expanded downwardly so as to cover the center pillar from the above. As a result, even when there is an occupant compartment projection having a relatively large projection amount such as a slip joint at an area where the airbag body is inflated, the lower portion of the airbag body is inflated and expanded so as to cover the occupant compartment projection. Accordingly, the lower portion of the airbag body is prevented from being caught up by the occupant compartment projection having a relatively large projection amount, thereby improving further the expansion performance of the airbag body.
According to a fifth aspect of the invention, in the fourth aspect, the turning-back line is set above a predetermined occupant compartment projection disposed at the occupant compartment inner side of the pillar.
According to this aspect, in addition to the operation of the fourth aspect, when the airbag body is inflated, the roll of the rolled portion of the airbag body is unrolled at a position above a predetermined occupant compartment projection, for example a slip joint, disposed at an occupant compartment inner side of the center pillar, and thereafter the turned-back portion is expanded downwardly from this position so as to cover the center pillar from the above. As a result, the turned-back portion of the airbag body is necessarily inflated and expanded during expansion so as to cover the predetermined occupant compartment projection disposed the occupant compartment inner side. Therefore, the lower portion of the airbag body can securely be prevented to be caught up by the predetermined vehicle occupant compartment projection.
A sixth aspect of the invention is structured in the second aspect such that the upper portion is provided with a gas introducing path formed substantially linearly along the roof side rail on only a region corresponding to a portion of the airbag body positioned below the roof side rail, and one end of the gas introducing portion communicating with an inflator, and the airbag body formed only in its area positioned below the roof side rail with a plurality of inflating chambers communicating with the gas introducing path, wherein the airbag body is double folded or is not folded at the gas introducing path.
According to this aspect, in addition to the configuration of the second aspect, the gas introducing path is formed generally linearly along the roof side rail and the gas introducing path is double folded or it is not folded. As a result, since a gas flow resistance is reduced at the gas introducing path when the airbag body is expanded, gas flow from the inflator is made smooth, so that a time period lapsing until expansion of the airbag body is completed is not prolonged even at a side of the airbag which is farther from the inflator and it can be shortened.
Also, according to this aspect, since it is unnecessary to accommodate the duct 406 over the front pillar and the roof side rail, which is required in the conventional art (refer to FIG. 21), the mounting convenience of the airbag body can be improved. Furthermore, since the gas introducing path of the airbag body is formed at only a region corresponding to the roof side rail and the plurality of the inflating chambers are formed at only a region positioned below the roof side rail, the gas introducing path and the plurality of inflating chambers of the bulky airbag body can easily be accommodated in the roof side rail portion where an accommodating space for the airbag body can be secured easier than the front pillar portion. At this point, the mounting convenience of the airbag body can also be improved.
A seventh aspect is structured in the sixth aspect such that the inflator is disposed at a portion of a vehicle body which is positioned rearward a center pillar, and a cut-out portion is formed at a portion of the airbag body which inflates downward of the front pillar.
According to this aspect, since the cut-out portion is formed at a portion of the vehicle body which is far from the inflator and expanded downward of the front pillar, a volume of this portion of the folded airbag body is reduced. As a result, it becomes possible to accommodate a front portion of the airbag body even at a portion with a small accommodating space formed between the front pillar and a front pillar garnish.
An eighth aspect is structured in the sixth aspect such that the portion of the airbag body other than the gas introducing path is disposed in parallel with the gas introducing path on the occupant compartment inner side.
According to this aspect, when the inflator is actuated, the gas introducing path is first inflated and the portion of the airbag body other than the gas introducing path is moved toward the occupant compartment inner side. As a result, the airbag is expanded in the curtain shape while the portion of the airbag body other than the gas introducing path is rapidly being inflated toward the occupant compartment inner side. For this reason, when the airbag body is expanded, it is prevented from being caught up by the occupant compartment projection such as a slip joint projecting from the center pillar inward of the occupant compartment.
A ninth aspect is structured in the sixth aspect such that the inflator is disposed at a lower portion of the pillar, and the gas introducing path and the inflator are connected to each other through a gas guide tube.
According to this aspect, in addition to the structure of the sixth aspect, the inflator can be disposed at the lower portion of the pillar, for example, a lower portion of a front pillar or a lower portion of a rear pillar, and the volume of a portion of the folded airbag body accommodated in the pillar disposed with the inflator is reduced. As a result, the mounting conveniences of both the inflator and the airbag body are improved.
A tenth aspect is structured in the sixth aspect such that a spherical. portion having an sectional area larger than that of the gas introducing path is formed at a downstream end portion of the gas introducing path.
According to this aspect, in addition of the contents of the sixth aspect, when gas from the inflator reaches the downstream end portion of the gas introducing path, its pressure is reduced at the spherical portion having the larger sectional area from the gas pressure at the other portion of the gas introducing path. As a result, the downward end portion of the gas introducing path can be prevented from being injured due to the gas pressure.
An eleventh aspect of the invention is a head-protecting airbag apparatus where an airbag body inflated in a curtain shape is mounted in a folded state along a roof side rail across at least a center pillar, wherein the airbag body comprises:
a gas introducing path which is formed generally linearly along the roof side rail in only a region positioned below the roof side rail and whose one end communicates with an inflator; and
a plurality of inflating chambers which are formed only in a region positioned below the roof side rail and whose one ends communicate with the gas introducing path;
wherein one of non-folding and a double folding along the gas introducing path is effected on the gas introducing path of the airbag body.
According to this aspect, since it is unnecessary to accommodate the duct 406 over the front pillar and the roof side rail, which is required in the conventional art (refer to FIG. 21), the mounting convenience of the airbag body can be improved. Furthermore, since the gas introducing path of the airbag body is formed at only a region positioned below the roof side rail and the plurality of the inflating chambers are formed at only a region positioned below the roof side rail, the gas introducing path and the plurality of inflating chambers of the bulky airbag body can easily be accommodated in the roof side rail portion where an accommodating space for the airbag body can be secured easier than the front pillar portion. At this point, the mounting convenience of the airbag body can also be improved.
Furthermore, the gas introducing path is formed substantially linearly along the roof side rail and the gas introducing path is double folded or it is not folded. As a result, since a gas flow resistance is reduced at the gas introducing path when the airbag body is expanded, gas flow from the inflator is made smooth, so that a time period lapsing until expansion of the airbag body is completed is not prolonged even at a side of the airbag which is farther from the inflator and it can be shortened.
A twelfth aspect of the invention is a head-protecting airbag apparatus where an airbag body expanding in a curtain shape is disposed in a folded state along a roof side rail across at least a center pillar, comprising:
the airbag body including at least one of a bellows-folded portion and a rolled-up portion, provided at its upper portion with a generally linear gas introducing path formed in only a region positioned below the roof side rail, and provided with a plurality of inflating chambers whose upper portions communicating with the gas introducing path and which extend generally downwardly;
an inflator for generating gas;
a gas guide tube for connecting the gas introducing path and the inflator to each other;
a guide member for guiding the airbag body when the airbag inflates and;
straps, one ends of which are respectively connected to a lower and front end and a lower and rear end of the airbag body, the other ends thereof being fixed to portions of a vehicle body.